Field of the Invention
The invention relates to a method of producing a coil of flexible material wound in layers of figure-8s with the cross-overs in each layer progressing around the package but leaving a radial opening into the coil from the outside to the axial opening thereof.
Such coils may be produced for example as shown in Taylor U.S. Pat. No. 2,634,922 or Newman U.S. Pat. No. 3,666,200. It has been found however, when forming such coils, even in the case of a so-called off-the-face wind, that is a wind in which the path of the guide is at a substantial distance from the surface of the coil being wound, that the hole is apt to be curved.
An arrangement for preventing this curvature on an on-the-face wind, that is a wind in which the guide swings away from the package during the formation but is kept rather close to the surface, is shown in Wagner U.S. Pat. No. 3,747,861.